In some image forming apparatuses including at least one heater, a known technique has been used for shortening First Print Out Time (“FPOT”), which is a time taken by an image forming apparatus from receiving a print request to outputting the first page, while limiting power supply to the one or more heaters. For example, in one image forming apparatus, voltage application is executed two times during a half cycle of alternating current. More specifically, the first voltage application starts at a timing at which a phase angle of the alternating current becomes 0 (zero) degree and ends at a timing at which the phase angle becomes an angle smaller than π/2 radians. The second voltage application starts at a timing at which the phase angle becomes an angle greater than π/2 radians but smaller than π radians and ends at a timing at which the phase angle becomes π radians. The timing at which the first voltage application ends and the timing at which the second voltage application starts are determined based on, for example, data obtained by, for example, experiment in advance.